csky: don't let sigreturn play with priveleged bits of status register
csky restore_sigcontext() blindly overwrites regs->sr with the value
it finds in sigcontext. Attacker can store whatever they want in there,
which includes things like S-bit. Userland shouldn't be able to set
that, or anything other than C flag (bit 0).
Do the same thing other architectures with protected bits in flags
register do - preserve everything that shouldn't be settable in
user mode, picking the rest from the value saved is sigcontext.
Signed-off-by: Al Viro <email@example.com>
Signed-off-by: Guo Ren <firstname.lastname@example.org>
1 file changed